Level 1

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DHCP lease not renewing

Hi all,

I currently have an Airport Extreme base station 5th generation in a small office setting. I am required by one of my software vendors to have a static IP address and port forwarding enabled. Recently, I have had several pieces of equipment lose their connection to the router. I have completely reset the router, recreated the configuration from scratch (not imported), have even had Apple replace the base station so it's unlikely it's a hardware issue. I have also tried reverting the firmware to 7.6.1 as I thought I may have updated to 7.6.3 shortly before this all happened but still no luck. I have had my ISP verify all the modem settings were correct.

I have a computer with Airport Utility 5.6 on it so I was able to do a little more digging and in the advanced tab under DHCP clients, I noticed that several clients had leases that expired in 1953 but were not renewing. I would reset the router (disconnect and reconnect power) and all would be good for a day or two and then it would happen again. I have tried adjusting the DHCP range and lease time with no luck either. I have talked to Apple support multiple times and have verified all the settings and have been told everything should be working. I am completely stumped. Apple support did indicate that it may have something to do with the static ip configuration as that's not a fully supported feature but it's beeng working fine for over a year now with no problems. As I can best recall, nothing changed right before the problem developed so I am at a loss of what further troubleshooting steps to take.

Has anyone seen or had a problem like this? Any sugestions?

Any help would be greatly appreciated.

Thanks!

Airport Extreme-OTHER, Mac OS X (10.7.5)

Posted on Aug 19, 2013 11:26 AM

25 replies

R C-R

Level 6

17,794 points

Aug 22, 2013 3:36 PM in response to ibraces

All I could find for the Arris brand of modem that might help is at http://www.dslreports.com/faq/16768 & the links it connects to, plus a mention of "admin" being teh login password at http://www.dslreports.com/forum/r27769987-Arris-admin-password-

No indication of if the modem even has accessible logs, though. Sorry I could not be of more help.

Aug 22, 2013 3:42 PM in response to ibraces

Apart from Student Day in Iran (Students fallen for freedom Dec.7, 1953) and an episode of the Honeymooners, that's all I got 😐

Might be time to get Apple involved, good luck.

regards

John Galt

Level 10

155,798 points

Aug 22, 2013 7:23 PM in response to ibraces

Thanks!

This was unexpected:

I have never seen it return anything other than the IP addresses corresponding to Apple's ntp time servers, and those others correspond to mine. For it to return a text string was unexpected and may be the best clue yet. It appears as though the query is being redirected to an internal time server - internal to your network.

Try this: Launch Terminal - it's also in your Utilities folder. At the prompt copy / paste or type the following line:

cat /etc/ntp.conf

What does it return?

Repeat for the other Macs on your network and make sure they are all identical.

R C-R

Level 6

17,794 points

Aug 22, 2013 8:10 PM in response to John Galt

John Galt wrote:

This was unexpected:

For what little it's worth, here is what I get on my iMac running Mountain Lion 10.8.4:

(8.8.8.8 at the bottom refers to Google's DNS servers.)

R C-R

Level 6

17,794 points

Aug 23, 2013 3:50 AM in response to ibraces

After doing some more digging, I found the ARRIS Router Setup - Web GUI User’s Guide on the Arris site. I don't know if it applies to your cable modem, but if it does section 3.22 Utilities – Using System Logs (page 31) indicates Arris modems do have an accessible log.

An earlier section, 2.2 Configuring Your Wireless Network (page 10), indicates you can disable the modem's wireless network. I am assuming you have done this, connected the Airport Extreme's WAN port to the modem's Ethernet port, & are relying on the Airport's radios for wireless connectivity. If not, maybe having both the modem's radio & the Airport's ones running at the same time is somehow causing this bizarre effect?

ibraces Author

Level 1

0 points

Aug 23, 2013 8:55 AM in response to John Galt

I think we're getting close! I found one computer (server) that returned "time.apple.comboserver" in the ntp.conf file. I couldn't figure it out all night then it hit me this morning. I abbreviate the name of our business a lot with our computers so "boserver" is our server name and has somehow been appended to the end of the time server. Why the router is being affected by this is beyond me but I think fixing it on this computer may solve the problem.

The computer is a Mac Mini running OS 10.7 and Mac OS X Server. How do I edit that file? I tried just going to Date & Time in System Preferences but that looks normal.

Thanks so much! I'm hoping we are near the end... This has been driving me (and the staff) nuts!

BDAqua

Level 10

250,259 points

Aug 23, 2013 11:13 AM in response to ibraces

Seems to be a simple text file in...

/private/etc/ntp.conf

Migh have to add Write rights to edit it.

John Galt

Level 10

155,798 points

Aug 23, 2013 12:44 PM in response to ibraces

ibraces wrote:

I think we're getting close! I found one computer (server) that returned "time.apple.comboserver" in the ntp.conf file. ... I think fixing it on this computer may solve the problem.

I think so too. That would confirm my suspicion that the Extreme is receiving a response from an internal time server rather than time.apple.com. If that's the case the erroneous response is periodically being issued by your Mini server to the Extreme, resulting in its clock being erronenously set.

I believe the file is a plain ASCII text file as BDAqua wrote, and editing it to remove the appended "boserver" characters from the name will be instructive. Unfortunately I am not using a Mac that I can test at the moment, but if you are willing to perform that change at your own risk it will advance troubleshooting. If you use a text editor be sure to save it in the same file format otherwise it will become unreadable to OS X.

You will need to authenticate with your Admin credentials to edit the file... don't change its permissions.

The reason the extraneous characters were appended to the file is a complete mystery, and if the reason isn't determined the problem may recur.

R C-R

Level 6

17,794 points

Aug 23, 2013 1:48 PM in response to BDAqua

FWIW, on my Macs the contents of the /private/etc/ntp.conf file is simply "server time.apple.com" (without the quotes). 22 bytes including (I assume) an end of line character.

Also see the man page for ntp.conf(5) for some interesting info about it (including the warning).

On my Macs, there is a related /private/etc/ntp-restrict.conf file with two "includefile" entries. /private/etc/ntp.conf is one of them; the other is /private/etc/ntp_opendirectory.conf. On my Mac, that second open directory file just contains the comment line "# opendirectory peers."

It might be worth checking that file as well.

ibraces Author

Level 1

0 points

Aug 23, 2013 7:07 PM in response to John Galt

Well, that was a let down...

I contacted Apple to help figure out how to edit that ntp.conf file and what was changing it. Turns out that what I thought was appendinging on to the file contents was actually the command prompt for the next line, it just wasn't going to the next line. I'm an idiot. Sorry.

Anyways... It appears that all the ntp.conf files are fine.

So far, the date has not been reset to 1953 (yet) and the only thing I've done differently was turning off my networked NAS drive. This is the longest it's been since I have had to reboot the router so I'm going to leave the NAS unplugged and see if that's the culprit. It's the only other thing I can think of on the network that was added recently and would possibly have the capability to screw up network traffic.

Thanks everyone for the help. If it's not the NAS I'm kind of out of ideas at this point. Apple has escalated it so perhaps they'll discover the source of this.

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DHCP lease not renewing